The invention relates to an automatic handling device for flexible flat products, in particular catamenial products such as sanitary towels, pantiliners or the like, as well as to an intermediate stacker unit to be used in this handling device.
In the fabrication of the afore-said products, automatic handling during the virtual manufacturing process and subsequent packaging process poses special problems because of the flexibility and irregular shape of the products. Defined and gentle product treatment must be ensured for the manufacturing and subsequent packaging process to be performed reliably and with as little susceptibility to failure as possible.
The most varying handling devices for various flexible products are known from prior art. For instance, EP 0 356 654 A1 teaches an apparatus for the supply of packing blanks to a packaging machine in which cassettes are used that are open at the top. They comprise several stacks of blanks one beside the other. By means of a corresponding automatic conveyor, the cassettes are placed on a cassette conveyor which is disposed on the rear of the packaging machine, simultaneously serving as a storage area for a multitude of filled cassettes. In the vicinity of a discharging station, the stacks of blanks are successively removed from the cassettes and, by upward motion and ensuing transverse motion, supplied to one or several magazines of blanks of the packaging machine.
EP 0 465 207 B1 teaches a method and an apparatus for packaging resiliently deformable articles into a box-shape by using a sheet of film, in which the stack to be packaged is inserted into an inner cassette. The latter cooperates with an outer cassette and corresponding folding, overlapping and sealing means with a sheet of film placed in between so as to form a closed wrap around the said stack.
DE 43 42 112 C1 relates to an apparatus for the grouped packaging of filled tea bags, in which a stacking shaft is used for forming and fixing the row of bags. In the inlet area of the stacking shaft, retaining fingers which are fixed in the lengthwise direction are provided together with lengthwise displaceable bag holding means, the tea bags which are individually supplied by bag advancing means being positioned between them.
It is the object of the present invention to have an automatic handling device comply as optimally as possible with the processing requirements of flat flexible products and in particular of catamenial products such as sanitary towels, pantiliners or the like so as to obtain high output rates accompanied with little susceptibility to failure. Due to the conventional structure of the manufacturing plant on the one hand and the packaging station on the other, the products are transferred from a continuous flow of serially supplied products into individual compartments of modular, continuously moving intermediate stacker units for the products thereby to be led off to the packaging machine.
In accordance with the invention, the automatic handling device, for the purpose of this transfer, comprises
conveying means on the infeed side for the serial guidance of the supplied products in a main infeed direction,
conveying means on the outfeed side for the intermediate stacker units, the compartments of which are charged with products, to be led off in a main outfeed direction which is perpendicular to the main infeed direction, and
a feed head for the products between the conveying means on the infeed side and on the outfeed side, which oscillates about a pivoting axis in the plane spanned by the main infeed and outfeed direction such that, during the oscillating motion in the main outfeed direction, the end of the feed head that is turned towards the respective intermediate stacker unit is synchronous with the respective compartment of the intermediate stacker unit for a product to be transferred into this compartment, and that, during the oscillating motion in the opposite direction, it orients itself toward the next compartment.
The gist of the invention resides in the oscillating feed head which ensures the intermediate stacker units to move continuously. This is of advantage since as a rule these intermediate stacker units are moved ahead by a comparatively voluminous chain drive, the stop and go operation of which, in the case of conventional handling devices, causes considerable strain on the handling device accompanied with corresponding wear because of the high inertias. In the case of the subject matter of the invention, only the feed head has to perform a discontinuous motion, which is by far easier to control in terms of machine equipment. Finally, as a result of the use of an intermediate stacker unit, the flexible products are properly guided during handling and kept definedly positioned for a subsequent packaging process. Consequently, a stacking job which is conventionally necessary for the flexible flat products can be carried out at a high speed, the stability of the stacking process being maintained and the mechanical strain on the plant being reduced.
Preferred embodiments of the handling device relate to the conveying means on the infeed side, to the design of the feed head in the form of an oscillating slotted block as well as the configuration of the intermediate stacker units as a conveying cassette having at least one take-up slot for the flat products.
As already mentioned at the outset, the invention also relates to an intermediate stacker unit in particular to be used in the afore-said handling device in a configuration as a conveying cassette having at least one slot. Preferred embodiments of the intermediate stacker unit relate to the shaping of this slot and especially to its contours. These are of special importance in particular in the handling of catamenial products such as sanitary towels or pantiliners, since these articles have inherent variations in curvature and orientation in the delivery from the production line. The intermediate stacker unit in the form of a conveying cassette can compensate for these variations.
A substantial advantage of the conveying cassette slots contoured according to the invention resides in that on the one hand a wide opening is formed for the insertion of the product into the slot, which maximizes the so-called process window for the infeed of the product into the cassette. Simultaneously, during outfeed, a very accurately defined outfeed position of the product is produced by the narrowed section of the slot, which renders this handling job likewise more reliable.